Formal semantics of extended hierarchical state transition matrix by CSP

The Extended Hierarchical State Transition Matrix (EHSTM) is a table-based modeling language frequently used in industry for specifying behaviors of a system. However, assuring correctness, i.e., having a design satisfy certain desired properties, is a non-trivial task. To address this problem, a model checker dedicated to EHSTMs called Garakabu2 is developed. However, there is no formal justification of Garakabu2, since its semantics has never been fully formalized. In this paper, we give a formal semantics to EHSTM by translating it into CSP, Communicating Sequential Processes. Our semantics covers most of the features supported by Garakabu2. We manually translate the small examples of EHSTM to CSP, and verify them by PAT, a CSP based model checker. We also verify the examples directly using Garakabu2 and show the result are same. The experiments also show that verification using our translation and PAT is much faster than that of Garakabu2 for checking message type EHSTM.